title: On the asymmetry of biological frequency distributions.
abstract: The long-standing problem of determining whether the skewness in a sample frequency distribution is the manifestation of the intermixing of disparate groups characterizable by a normal mixture distribution or the manifestation of non-mixture, skew-producing determinants is discussed. Biometrical tools for modeling and quantifying the significance of the skewness in a trait of interest that invite interpretations other than those formed in mixtures or "subgroups" are elaborated. Statistical methods for testing whether a normal mixture distribution better characterizes a set of data than the proposed (or any other) skewed, single-population-oriented models are offered. The power of these tests is examined through Monte Carlo experimentation. A brief application in hypertension research demonstrates some of the problems and methods discussed in the paper.
authors.affiliation: Department of Medicine, University of Michigan, Ann Arbor 48109-0500.
authors.forename: N J
authors.initials: NJ
authors.lastname: Schork
authors.forename: A B
authors.initials: AB
authors.lastname: Weder
authors.forename: M A
authors.initials: MA
authors.lastname: Schork
mesh_terms: D001794:Blood Pressure / Q000235:genetics; D005821:Genetic Techniques; D006801:Humans; D015233:Models, Statistical; D009010:Monte Carlo Method; D016011:Normal Distribution; D013223:Statistics as Topic